/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.optimize.peephole;

import proguard.classfile.Clazz;
import proguard.classfile.constant.*;
import proguard.classfile.constant.visitor.ConstantVisitor;
import proguard.classfile.util.*;

/**
 * This ConstantVisitor delegates to a given constant visitor, except for constants that contain wildcards (indices
 * larger than 0xffff).
 *
 * @see InstructionSequenceMatcher
 * @author Eric Lafortune
 */
public class WildcardConstantFilter implements ConstantVisitor {
    private static final int WILDCARD = InstructionSequenceMatcher.X;

    private final ConstantVisitor constantVisitor;

    private final MyWildcardChecker wildcardChecker = new MyWildcardChecker();

    /**
     * Creates a new WildcardClassReferenceInitializer that delegates to the given constant visitor.
     */
    public WildcardConstantFilter(ConstantVisitor constantVisitor) {
        this.constantVisitor = constantVisitor;
    }

    // Implementations for ConstantVisitor.

    public void visitIntegerConstant(Clazz clazz, IntegerConstant integerConstant) {
        constantVisitor.visitIntegerConstant(clazz, integerConstant);
    }

    public void visitLongConstant(Clazz clazz, LongConstant longConstant) {
        constantVisitor.visitLongConstant(clazz, longConstant);
    }

    public void visitFloatConstant(Clazz clazz, FloatConstant floatConstant) {
        constantVisitor.visitFloatConstant(clazz, floatConstant);
    }

    public void visitDoubleConstant(Clazz clazz, DoubleConstant doubleConstant) {
        constantVisitor.visitDoubleConstant(clazz, doubleConstant);
    }

    public void visitPrimitiveArrayConstant(Clazz clazz, PrimitiveArrayConstant primitiveArrayConstant) {
        constantVisitor.visitPrimitiveArrayConstant(clazz, primitiveArrayConstant);
    }

    public void visitStringConstant(Clazz clazz, StringConstant stringConstant) {
        if (!containsWildcard(clazz, stringConstant)) {
            constantVisitor.visitStringConstant(clazz, stringConstant);
        }
    }

    public void visitUtf8Constant(Clazz clazz, Utf8Constant utf8Constant) {
        constantVisitor.visitUtf8Constant(clazz, utf8Constant);
    }

    public void visitInvokeDynamicConstant(Clazz clazz, InvokeDynamicConstant invokeDynamicConstant) {
        if (!containsWildcard(clazz, invokeDynamicConstant)) {
            constantVisitor.visitInvokeDynamicConstant(clazz, invokeDynamicConstant);
        }
    }

    public void visitMethodHandleConstant(Clazz clazz, MethodHandleConstant methodHandleConstant) {
        constantVisitor.visitMethodHandleConstant(clazz, methodHandleConstant);
    }

    public void visitFieldrefConstant(Clazz clazz, FieldrefConstant fieldrefConstant) {
        if (!containsWildcard(clazz, fieldrefConstant)) {
            constantVisitor.visitFieldrefConstant(clazz, fieldrefConstant);
        }
    }

    public void visitInterfaceMethodrefConstant(Clazz clazz, InterfaceMethodrefConstant interfaceMethodrefConstant) {
        if (!containsWildcard(clazz, interfaceMethodrefConstant)) {
            constantVisitor.visitInterfaceMethodrefConstant(clazz, interfaceMethodrefConstant);
        }
    }

    public void visitMethodrefConstant(Clazz clazz, MethodrefConstant methodrefConstant) {
        if (!containsWildcard(clazz, methodrefConstant)) {
            constantVisitor.visitMethodrefConstant(clazz, methodrefConstant);
        }
    }

    public void visitClassConstant(Clazz clazz, ClassConstant classConstant) {
        if (!containsWildcard(clazz, classConstant)) {
            constantVisitor.visitClassConstant(clazz, classConstant);
        }
    }

    public void visitMethodTypeConstant(Clazz clazz, MethodTypeConstant methodTypeConstant) {
        if (!containsWildcard(clazz, methodTypeConstant)) {
            constantVisitor.visitMethodTypeConstant(clazz, methodTypeConstant);
        }
    }

    public void visitNameAndTypeConstant(Clazz clazz, NameAndTypeConstant nameAndTypeConstant) {
        if (!containsWildcard(clazz, nameAndTypeConstant)) {
            constantVisitor.visitNameAndTypeConstant(clazz, nameAndTypeConstant);
        }
    }

    public void visitModuleConstant(Clazz clazz, ModuleConstant moduleConstant) {
        if (!containsWildcard(clazz, moduleConstant)) {
            constantVisitor.visitModuleConstant(clazz, moduleConstant);
        }
    }

    public void visitPackageConstant(Clazz clazz, PackageConstant packageConstant) {
        if (!containsWildcard(clazz, packageConstant)) {
            constantVisitor.visitPackageConstant(clazz, packageConstant);
        }
    }

    // Small utility methods.

    /**
     * Checks whether the given constant contains wildcard indices.
     */
    private boolean containsWildcard(Clazz clazz, Constant constant) {
        wildcardChecker.containsWildcard = false;
        constant.accept(clazz, wildcardChecker);
        return wildcardChecker.containsWildcard;
    }

    private static class MyWildcardChecker extends SimplifiedVisitor implements ConstantVisitor {
        public boolean containsWildcard;

        // Implementations for ConstantVisitor.

        public void visitAnyConstant(Clazz clazz, Constant constant) {}

        public void visitStringConstant(Clazz clazz, StringConstant stringConstant) {
            if (stringConstant.u2stringIndex >= WILDCARD) {
                containsWildcard = true;
            }
        }

        public void visitInvokeDynamicConstant(Clazz clazz, InvokeDynamicConstant invokeDynamicConstant) {
            if (invokeDynamicConstant.u2nameAndTypeIndex >= WILDCARD) {
                containsWildcard = true;
            } else {
                // Recursively check the referenced constant.
                clazz.constantPoolEntryAccept(invokeDynamicConstant.u2nameAndTypeIndex, this);
            }
        }

        public void visitAnyRefConstant(Clazz clazz, RefConstant refConstant) {
            if (refConstant.u2classIndex >= WILDCARD || refConstant.u2nameAndTypeIndex >= WILDCARD) {
                containsWildcard = true;
            } else {
                // Recursively check the referenced constants.
                clazz.constantPoolEntryAccept(refConstant.u2classIndex, this);
                clazz.constantPoolEntryAccept(refConstant.u2nameAndTypeIndex, this);
            }
        }

        public void visitClassConstant(Clazz clazz, ClassConstant classConstant) {
            if (classConstant.u2nameIndex >= WILDCARD) {
                containsWildcard = true;
            }
        }

        public void visitMethodTypeConstant(Clazz clazz, MethodTypeConstant methodTypeConstant) {
            if (methodTypeConstant.u2descriptorIndex >= WILDCARD) {
                containsWildcard = true;
            }
        }

        public void visitNameAndTypeConstant(Clazz clazz, NameAndTypeConstant nameAndTypeConstant) {
            if (nameAndTypeConstant.u2nameIndex >= WILDCARD || nameAndTypeConstant.u2descriptorIndex >= WILDCARD) {
                containsWildcard = true;
            }
        }

        public void visitModuleConstant(Clazz clazz, ModuleConstant moduleConstant) {
            if (moduleConstant.u2nameIndex >= WILDCARD) {
                containsWildcard = true;
            }
        }

        public void visitPackageConstant(Clazz clazz, PackageConstant packageConstant) {
            if (packageConstant.u2nameIndex >= WILDCARD) {
                containsWildcard = true;
            }
        }
    }
}
